Traditional turf lawns dominate urban landscapes, deplete the soil and provide no food for pollinators. A pollinator lawn is a flowering carpet of native plants and grasses that requires no pesticide, herbicide or weed and feed treatments, needs very little mowing, can take foot traffic and feeds pollinators. Use fescue grasses such as fine fescue with white dutch clover and other low growing plants such as lanceleaf coreopsis, blanket flower, and pussy toes. There are many components to a turf IPM program, including monitoring for pest activity, establishing tolerance levels, and considering cultural and biological control strategies.
Principles of Turf Best Managment Practices
- Protect soil from erosion. Healthy, properly managed turf is excellent at holding onto soil and preventing erosion.
- Proper identification of problems. When turf damage is noticed and before applying pesticides, make sure insects and not diseases or some abiotic factor are the cause of the damage. Turf damage may be caused by fungal diseases, abiotic conditions, and improper maintenance.
- Use Integrated Pest Management (IPM) to control insect pests and weeds. IPM is an approach that employs monitoring of plants, pests and weather to project ahead and plan. IPM addresses the source of pest problems, whereas pesticides simply respond to the pest. Ultimately, IPM helps in reducing pesticides, which is a key component in creating pollinator-friendly habitat. Pesticides are harmful to pollinators and beneficial insects. Healthy urban landscapes can be maintained with little or no pesticide use. Instead of routinely spraying for insects, spot treat only when necessary with soft pesticides such as soaps and oils.
Turf damage: is it insect or fungus?
Identification: Properly identify the insect or disease through morphology or type of damage Detecting the presence of an insect is the first step in good insect control. When you find the insect, examine it closely to identify it to species.
Damage: Distinquish between insect and pathogen damage
If the turf looks damaged, wilted, and water-starved, then an insect may be involved. During root feeding, insect species that feed on roots detach the thatch and blades from the roots and permit the sod to peel off the soil without any root attachment. In addition, some insects defoliate or suck the grass blades. You must search in the blades and thatch to find these insects. Blade defoliation damage appears as brown scars where the blades are clipped off by the insect. Blade sucking damage appears as brown lesions where the blade's sap was removed by the insect. Many times an area of turf is brown and damaged, but damaging insects cannot be found. Search for the insects along the margin of brown and green grass.
When turf damage is noticed and before applying pesticides, make sure insects and not diseases or some abiotic factor are the cause of the damage. Turf damage may be caused by fungal diseases, abiotic conditions, and improper maintenance. For pathogen identification, contact the Plant Disease Clinic at the University of Minnesota, 1519 Gortner Ave, 105 Stakeman Hall, 612.625.1275, [email protected]
Be sure to examine an area of turf that contains living as well as damaged grass. The most serious insects of turf feed on living turf and are not found in dead areas. Insects found in completely dead patches generally are not responsible for the damage. Methods are available for discovering insects in turf. Cutworms, sod webworms, aphids, chinch bugs, and other blade defoliating and blade sucking insects can be detected by the flotation method. Use a large coffee can with both ends removed and sink it into the turf. Mix one ounce of liquid dish washing detergent into one gallon of water and pour the soapy water into the container. In a few minutes, the soapy water will irritate the insect, the insect will release its grasp, and the insect will float.
Root-feeding insects such as white grubs and billbugs will not respond to the flotation method. Grubs feed by separating grass blades. Billbug larvae are legless and live inside the grass sheath and do not separate blades from roots until the last larval stage (instar). Sample grubs and billbugs by looking for insects in grass roots and in the soil layer beneath the roots. If infestations are heavy, the grubs will have removed most of the grass roots and the turf will roll back like a carpet.
Integrated Pest Management (IPM) is a decision-making process that includes scouting, damage threshold,control options, and timing of insecticide application. IPM practices conserve beneficial insects and promote pesticide usage at the vulnerable stage in the pest's life history.
Steps to Implementing Turf Best Managment Practices
- Routinely inspect or scout the turf. Identify insects, diseases, and damage.
- Determine changes in cultural practices that can increase turf health and vigor.
- Determine what is an acceptable threshold of pest damage.
- Time the pesticide application to the vulnerable stage in the insect's life history.
- Keep records of the damage location, date, and chemical. Return to step 1.
Identification of insect or disease. This is called scouting. Look for discoloration, defoliation, and separation of grass from roots. When investigating turf damage, pay particular attention to whether the damage spreads. After detecting insects, the next step is to determine if the insects are pests, harmless, or beneficial. Only pest insects warrant treatment. Thresholds have been established for some turf insects. Thresholds are the maximum number of insects per specified area that can be tolerated without obvious turf injury. Often thresholds are general and not specific guidelines, because other factors influence damage, such as drought, grass cultivar, and traffic and compaction of the grass. For example, heavily fertilized golf courses usually contain the most insects. In Minnesota, most home lawns fungi cause more damage than insects. After locating the damaging insect, time insecticide usage to the vulnerable stage of the pest. Insects are often more susceptible to treatment in a certain stage in their development, often when the immatures are actively feeding. Also, the judicious use of conventional insecticides helps preserve beneficial insects that naturally regulate pest insects. Applying scheduled sprays, without determining if the insect is present, can lead to expensive pesticide applications, create pest populations resistant to the pesticide, and disrupt the natural control by beneficial insects in the turf.
Spread insecticide granules uniformly over the lawn. A fertilizer spreader may be used if it is calibrated properly. Follow the pesticide label directions. Use a compressed air sprayer to apply at least 2 or 3 gallons for each 1,000 square feet. The hose-on type sprayer, which delivers a coarse droplet spray, may be used. Most wettable powders don't work well in the hose-on sprayers. For blade feeding insects, do not water for two to three days following treatment. Allow the lawn to dry after treatment before letting children and pets play on it. Read the pesticide label and follow the instructions as a final authority on pesticide use.
To control root feeding insects such as grubs and billbug larvae, thoroughly water the lawn immediately after treatment. A microbial insecticide, Bacillus thuringiensis galleriae, GrubGone, can be used to mange grubs in bee lawns where pollinators need to be protected. Chlorantraniliprole (Scott's Grub-Ex), is an outstanding grub control and can be used in bee lawns and on foliage for Japanese beetle. Although it is bee friendly, it is highly toxic to butterfly adults and larvae.
The neonicotinoids clothianidin, thiamethoxam, and imidacloprid are slow acting in soils, but have long residual activity against grubs and other pests all summer. However, the neonicotinoids can kill ground nesting bees, and can be move systemically into pollen and nectar of clover and other lawn flowers causing sublethal effects on behavior or lethal effects on survival.
Neonicotinioids or herbicides are not recommended for managing insects in bee lawns.